co_consts are merged already, but I forget about code attributes other than co_consts. Duplication ratio is vary by code style, but in case of logging, we can reduce 25% of them. ``` >>> data = open('Lib/logging/__pycache__/__init__.python-310.pyc', 'rb').read() >>> import marshal >>> x = [] >>> def walk(c): ... x.append(c.co_code) ... x.append(c.co_lnotab) ... for cc in c.co_consts: ... if hasattr(cc, 'co_code'): ... walk(cc) ... >>> code = marshal.loads(data[16:]) >>> walk(code) >>> len(x) 336 >>> len(set(x)) 249 >>> 249/336 0.7410714285714286 ```

Do you mean sharing values of co_code and co_lnotab between code objects of the same module? How much memory does this save (in absolute and relative value)? Which functions have the same co_code?

PEP 626 has just been accepted. Could you please leave this until I have merged in the implementation of PEP 626 which uses a different line number table format

@Serhiy > Do you mean sharing values of co_code and co_lnotab between code objects of the same module? Yes. > How much memory does this save (in absolute and relative value)? Maybe 1~3%, but I am not sure. I am more interested in reducing number of objects, because it will reduce import time. Additionally, co_code is used while executing code. Unlike other cold data (e.g. docstring, annotations), sharing co_code will improve CPU cache utilization. > Which functions have the same co_code? For example, ``` # logging/__init__.py @property def manager(self): return self.logger.manager ... @property def name(self): return self.logger.name ``` Such simple functions are very common in OO-style code. @Mark Shannon Sure.

 New changeset bdb941be423bde8b02a5695ccf51c303d6204bed by Inada Naoki in branch 'master': bpo-42217: compiler: merge same co_code and co_linetable objects (GH-23056) https://github.com/python/cpython/commit/bdb941be423bde8b02a5695ccf51c303d6204bed